Generally, vehicles are provided with a variety of valve apparatuses. Such valve devices are configured to distribute or control the flow of different kinds of fluids that are provided depending on the purposes, such as cooling an engine, air conditioning of a passenger compartment, exhaust gas recirculation (of an EGR system), etc.
Of a variety of valve apparatuses, rotary valves include: a valve body having two or more ports; and a valve member configured to be rotated around a rotating shaft in the valve body so as to selectively open or close the two or more ports. Such rotary valves are mainly used in coolant circulation circuits of internal combustion engines.
A representative example of such rotary valves was proposed in U.S. Pat. No. 6,315,267 B1 (hereinafter, referred to as ‘Patent document 1’). The rotary valve according to this conventional technique includes: a valve body having a valve chamber with an inlet port and outlet port, each communicating with the valve chamber; a cylindrical valve member disposed in the valve chamber so as to be rotatable between an open and closed position; a resilient seal member that has a curved shape and is disposed between the valve member and either the inlet port or the outlet port; a torque motor attached to the valve body so as to rotate the valve member; and a spring means for elastically biasing a rotor of the torque motor and the valve member to the open position.
In the rotary valve according to the conventional technique, when the inlet port or the outlet port of the valve body is opened by rotation of the valve member, the resilient seal member is elastically interposed between the valve member and the corresponding portion of the valve body, thus preventing fluid from leaking through the inlet port or the outlet port.
However, the conventional rotary valve is disadvantageous in that the sealability of the inlet or outlet port of the valve body is comparatively low because of insufficient resilience of the resilient seal member, and leakage of fluid cannot be reliably prevented.